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Significance of the strain-dominated region around a vortex on induced aerodynamic loads

Published online by Cambridge University Press:  14 May 2021

Karthik Menon Open the ORCID record for Karthik Menon [Opens in a new window]  and
Rajat Mittal Open the ORCID record for Rajat Mittal [Opens in a new window]
Karthik Menon*
Affiliation:
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD21218, USA
Rajat Mittal*
Affiliation:
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD21218, USA
*
†Email addresses for correspondence: kmenon@jhu.edu, mittal@jhu.edu
†Email addresses for correspondence: kmenon@jhu.edu, mittal@jhu.edu
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Abstract

The ability of vortices to induce aerodynamic loads on proximal surfaces plays a significant role in a wide variety of flows. However, most studies of vortex-induced effects primarily focus on analysing the influence of the rotation-dominated cores of vortices. In this work, we show that not only are vortices in viscous flows surrounded by strain-dominated regions, but these regions are dynamically important and can sometimes even dictate the induced aerodynamic loads. We demonstrate this for a pitching airfoil, which exhibits dynamic stall and generates several force-inducing vortices. Using a data-driven force partitioning method (FPM), we quantify the influence of vortices as well as vortex-associated strain to show that our current understanding of vortex-dominated phenomena, such as dynamic stall, is incomplete without considering the substantial effect of strain-dominated regions that are associated with vortices.

JFM classification

Vortex Flows: Vortex shedding Vortex Flows: Vortex dynamics Wakes/Jets: Separated flows
Type
JFM Rapids
Information
Journal of Fluid Mechanics , Volume 918 , 10 July 2021 , R3
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Copyright
© The Author(s), 2021. Published by Cambridge University Press

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